producing new cells 2.1

Question 1

what are chromosomes

Answer 1

threadlike structures composed of DNA

Question 2

where are chromosomes found

Answer 2

in the nucleus of plant, animal and fungal cells

Question 3

how many chromosomes does every cell in our body’s have

Answer 3

46 chromosomes

23 pairs

Question 4

what is in the structure of chromosomes

Answer 4

centromere and chromotid

Question 5

why is mistosis/cell division important

Answer 5

for growth, repair and to maintain the diploid chromosome complement

Question 6

stage 1 of mitosis

Answer 6

starts with a diploid parent cell. the nucleus containing long uncoiled chromosomes become visible under a microscope

Question 7

stage 2 of mitosis

Answer 7

chromosomes shorten and duplicate. chromosomes now consist of two identical chromatids

Question 8

stage 3 of mitosis

Answer 8

the nuclear membrane disintegrates and spindle fibres appear. the chromosomes line up at the equator of the cell

Question 9

stage 4 of mitosis

Answer 9

the spindle fibres contract, separating sister chromatids and pulling them to opposite poles of the cell

Question 10

stage 5 of mitosis

Answer 10

the cytoplasm divides and 2 new nuclear membranes form around each group of chromotids

Question 11

stage 6 of mitosis

Answer 11

two new daughter cells form, each with the same number of chromosomes as the parent cell

Question 12

diploid

Answer 12

a cell that has two matching sets of chromosomes

Question 13

examples of diploid cells

Answer 13

skin cells and zygote

Question 14

chromosome complement

Answer 14

the total number of chromosomes present in every cell of a species

Question 15

haploid

Answer 15

a cell that has a single set of chromosomes

Question 16

examples of haploid cells

Answer 16

sperm cells and egg cells

Question 17

chromotids

Answer 17

a single strand of a chromosome, which is replicated before mitosis

Question 18

stem cells are…

Answer 18

unspecialised cells

Question 19

what can stem cells do

Answer 19

reproduce themselves indefinitely by repeated mitosis and develop into various types of specialised cells

Question 20

types of stem cells

Answer 20

embryonic stem cell and adult tissue stem cell

Question 21

embryonic stem cells

Answer 21

• taken from early developing embryo

- can develop into any cell type found in the body

Question 22

tissue stem cells

Answer 22

• taken from tissues of an adult (brain, bone marrow and skin)
• can only differentiate into a specialised cell of the same tissue it was taken from

Question 23

why are stem cells important

Answer 23

for growth and repair

Question 24

what are specialised cells

Answer 24

cells which have adapted to preform a specific job

Question 25

organisation of the body

Answer 25

cells->tissues->organs->systems

Question 26

red blood cell structure

Answer 26

• biconcave disc
• no nucleus
• very small and flexible to be able to fit into capillaries

Question 27

red blood cell function

Answer 27

to transport oxygen around the body

Question 28

sperm cell structure

Answer 28

• has a tail to help it swim to the egg

- has many mitochondria so it has lots of energy to swim to the egg

Question 29

sperm cell function

Answer 29

to swim and fertilise the egg cell